1. Field of the Invention
The present invention is directed to a stable free aggregate of mineralized wood chips usable in wood concrete products, and a method of making the same.
2. Description of the Related Art
In wood concrete technology (WCT) fibrous organic materials such as wood chips (and hereinafter simply referred to as chips) are used as an aggregate in concrete. This technology is advantageous for sound and heat insulation since the wood chips have a low density. However, until recently, WCT has not been used in the U.S. because most of the industrial timber is grown in the southern and southeastern part of the U.S., and is not suitable for WTC. This is due in part to the fact that such woods, such as Southern Pine, contain substantial amounts of "cement poisons" which leach from the organic fibers aggregate into the cement mixture, and retard the hardening of the cement such that hardening times are unacceptable.
Applicants have previously developed a process known as K-X treatment for treating organic products WTC. The K-X treatment process includes forming a free aggregate of chips of fibrous organic products and encasing the individual chips with an inorganic mineralizing coating to a degree sufficient to seal in water-soluble organic matter, i.e., the cement poisons, held in the pores of the chips. This prevents the leaching of the cement poisons the individual chips when they are subsequently incorporated into a cement mixture. The resulting stable free aggregate can be stored without decaying and permits a relatively fast hardening time for the concrete (as little as 10 to 14 hours). The K-X treatment is disclosed in Applicants' U.S. Pat. No. 5,109,170, which is herein incorporated by reference.
However, while the K-X treatment represents a substantial improvement over the conventional WCT, its 10 to 14 hour hardening time is not entirely satisfactory. It would be desirable to instead produce an aggregate for WCT which can be used in concrete products having an even shorter hardening time.